[llvm] [llvm][GISel] Use computeKnownFPClass (PR #141484)

[Matt Arsenault via llvm-commits]

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@@ -74,7 +74,8 @@ define float @test_fmed3_maybe_SNaN_input_zero_third_operand_ieee_true_dx10clamp
 ; GFX10-LABEL: test_fmed3_maybe_SNaN_input_zero_third_operand_ieee_true_dx10clamp_true:
 ; GFX10:       ; %bb.0:
 ; GFX10-NEXT:    s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
-; GFX10-NEXT:    v_mul_f32_e64 v0, v0, 2.0 clamp
+; GFX10-NEXT:    v_mul_f32_e32 v0, 2.0, v0
+; GFX10-NEXT:    v_med3_f32 v0, v0, 1.0, 0
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arsenm wrote:

Regression 

https://github.com/llvm/llvm-project/pull/141484